Group A β-hemolytic Streptococcal Pharyngitis: An Updated Review

BACKGROUND

Group A ß-hemolytic Streptococcus (GABHS) is the leading bacterial cause of acute pharyngitis in children and adolescents worldwide.

OBJECTIVE

This article aims to familiarize clinicians with the clinical manifestations, evaluation, diagnosis, and management of GABHS pharyngitis.

METHODS

A search was conducted in December 2022 in PubMed Clinical Queries using the key term "group A β-hemolytic streptococcal pharyngitis". This review covers mainly literature published in the previous ten years.

RESULTS

Children with GABHS pharyngitis typically present with an abrupt onset of fever, intense pain in the throat, pain on swallowing, an inflamed pharynx, enlarged and erythematous tonsils, a red and swollen uvula, enlarged tender anterior cervical lymph nodes. As clinical manifestations may not be specific, even experienced clinicians may have difficulties diagnosing GABHS pharyngitis solely based on epidemiologic or clinical grounds alone. Patients suspected of having GABHS pharyngitis should be confirmed by microbiologic testing (e.g., culture, rapid antigen detection test, molecular point-of-care test) of a throat swab specimen prior to the initiation of antimicrobial therapy. Microbiologic testing is generally unnecessary in patients with pharyngitis whose clinical and epidemiologic findings do not suggest GABHS. Clinical score systems such as the Centor score and McIssac score have been developed to help clinicians decide which patients should undergo diagnostic testing and reduce the unnecessary use of antimicrobials. Antimicrobial therapy should be initiated without delay once the diagnosis is confirmed. Oral penicillin V and amoxicillin remain the drugs of choice. For patients who have a non-anaphylactic allergy to penicillin, oral cephalosporin is an acceptable alternative. For patients with a history of immediate, anaphylactic-type hypersensitivity to penicillin, oral clindamycin, clarithromycin, and azithromycin are acceptable alternatives.

CONCLUSION

Early diagnosis and antimicrobial treatment are recommended to prevent suppurative complications (e.g., cervical lymphadenitis, peritonsillar abscess) and non-suppurative complications (particularly rheumatic fever) as well as to reduce the severity of symptoms, to shorten the duration of the illness and to reduce disease transmission.

Social Media Utilization in Otolaryngology: A Scoping Review

OBJECTIVE

Social media (SM) is an increasingly popular medium for the medical community to engage with patients, trainees, and colleagues. This review aimed to identify reported uses of SM in otolaryngology-head and neck surgery (OHNS), assess the quality of evidence supporting these uses, and identify gaps in the literature. With the relative lack of regulatory guidelines for the development of SM content, we hypothesized that the quality of content available on SM would be highly variable.

DATA SOURCES AND METHODS

A scoping review was performed of English-language peer-reviewed studies published to date discussing SM use in any form within OHNS. Three reviewers independently screened all abstracts. Two reviewers independently extracted data of interest from the full text of articles identified from the preliminary abstract screen.

RESULTS

171 studies were included, with 94 (54.9%) studies published between 2020 and 2022. 104 (60.8%) studies were conducted in the US. 135 (78.9%) used cross-sectional or survey-based methodology; only 7 (4.1%) were controlled studies. SM was most commonly employed for professional networking (n = 37 [21%]), and within subspecialties of otology (n = 38 [22%]) and rhinology/allergy (n = 25 [15%]). Facebook was most frequently used for study recruitment (n = 23 [13.5%]), YouTube for patient education (n = 15 [14.6%]), and Twitter for professional networking (n = 16 [9.4%]).

CONCLUSION

SM use within OHNS is increasing rapidly, with applications including patient education, professional networking, and study recruitment. Despite myriad articles, there remains a paucity of well-controlled studies. As SM becomes integrated into healthcare, particularly for applications directly impacting patient care, higher levels of evidence are needed to understand its true impact. Laryngoscope, 133:2447-2456, 2023.

Invasive Infection With emm3/ST15 Streptococcus pyogenes: The First Case Report From China and Complete Genome Analysis

Streptococcus pyogenes (GAS) may cause severe invasive disease with a high fatality rate, especially M3-type strains, which are less common in China. Here, we report the first emm3/ST15 invasive GAS infection case in China. The patient was diagnosed with severe skin and soft tissue infection (SSTI) and septicaemia caused by one GAS strain. Antibiotic susceptibility tests showed that the isolate was susceptible to all tested drugs. Antimicrobial therapy was then applied, and the patient fully recovered and was discharged from the hospital on Day 43. Whole-genome sequencing was carried out using the Illumina and Oxford Nanopore platforms and revealed this to be the first emm3/ST15-type GAS invasive infection in China. The closely related emm3/ST15-type GAS strains are MGAS315 from the United States and M3-b from Japan. Our finding is a warning that we should pay attention to invasive M3-type GAS infections in China and indicates the global spread of the highly virulent emm3/ST15 GAS strain.

Invasive Multidrug-Resistant emm93.0 Streptococcus pyogenes Strain Harboring a Novel Genomic Island, Israel, 2017-2019

Invasive group A Streptococcus (iGAS) infections have increased in Israel since 2016 as successful lineages have emerged. We report the emergence and outbreak of a multidrug-resistant S. pyogenes emm93.0, sequence type 10, among iGAS infections in Israel since 2017. This type has been observed very rarely in other countries. During this period, emm93.0 was the cause of 116 infections in Israel and became the leading type during 2018. Most of the infections were from bacteremia (75%), and most patients were male (76%). We observed infections across Israel, mainly in adults. Of note, we observed multidrug resistance for clindamycin, tetracycline, and trimethoprim/sulfamethoxazole. Whole-genome sequencing confirmed clonality among geographically disseminated isolates. The local emm93.0 sequence type 10 clone contained a novel genomic island harboring the resistance genes lsa(E), lnu(B), and ant (6)-Ia aph(3')-III. Further phenotypic and genomic studies are required to determine the prevalence of this resistance element in other iGAS types.

A Review of Streptococcus pyogenes: Public Health Risk Factors, Prevention and Control

Streptococcus pyogenes, (colloquially named "group A streptococcus" (GAS)), is a pathogen of public health significance, infecting 18.1 million people worldwide and resulting in 500,000 deaths each year. This review identified published articles on the risk factors and public health prevention and control strategies for mitigating GAS diseases. The pathogen causing GAS diseases is commonly transmitted via respiratory droplets, touching skin sores caused by GAS or through contact with contaminated material or equipment. Foodborne transmission is also possible, although there is need for further research to quantify this route of infection. It was found that GAS diseases are highly prevalent in developing countries, and among indigenous populations and low socioeconomic areas in developed countries. Children, the immunocompromised and the elderly are at the greatest risk of S. pyogenes infections and the associated sequelae, with transmission rates being higher in schools, kindergartens, hospitals and residential care homes. This was attributed to overcrowding and the higher level of social contact in these settings. Prevention and control measures should target the improvement of living conditions, and personal and hand hygiene. Adherence to infection prevention and control practices should be emphasized in high-risk settings. Resource distribution by governments, especially in developed countries, should also be considered.

An emm5 Group A Streptococcal Outbreak Among Workers in a Factory Manufacturing Telephone Accessories

Ranked among the top10 infectious causes of death worldwide, group A Streptococcus (GAS) causes small- and large-scale outbreaks, depending on the trigger as transmission of a GAS strain or expansion of predominant clones. In China, GAS infections other than scarlet fever are not notifiable. In Shanghai, an epidemiological investigation was initiated after two successive severe pneumonia cases with one death in a digital factory, from where outbreaks are less widely reported. The investigation was performed using emm typing, pulsed-field gel electrophoresis (PFGE) typing, superantigen profiling, and genome analysis. This enabled characterization of relatedness among the outbreak isolates and identification of the mobile genetic elements present. Among 57 patients with respiratory symptoms investigated in the factory, emm5 GAS strains were isolated from 8 patients. The eight GAS infection cases comprising one fatal severe pneumonia case, six influenza-like illness cases, and one pharyngitis case. Two risk factors were identified: adult with an age of 18–20 years and close contact with a GAS patient or carrier. GAS attack rate was 14.0% (8/57), and GAS carriage rate was probably around 2.7% (14/521) based on surveys in two nearby districts. All the 10 outbreak associated isolates were assigned to emm5 and sequence type ST-99 (emm5/ST-99), harbored superantigen genes speC, speG, and smeZ, and were assigned to two similar PFGE patterns (clones). Among the outbreak associated isolates, all carried ermA with resistance to erythromycin and inducible resistance to clindamycin, and eight (80%) carried a tetM gene with resistance to tetracycline. Among the 14 carriage isolates, 12 were emm12/ST-36, and 2 were emm1/ST-28, all with superantigen genes speC, speG, ssa, and smeZ. All the carriage isolates harbored ermB and tetM with resistance to erythromycin, clindamycin, and tetracycline. Genome analysis showed the two outbreak clones were closely related and possessed new prophages carrying virulence gene sdc and antibiotic resistance genes of ermA and tetM, which were not found in the emm5 reference strain Manfredo. This is the first report of a GAS outbreak in this type of workplace. The outbreak was caused by two closely related emm5 clones that differed from the predominant emm types circulating in China.

A new genotyping scheme based on MLVA for inter-laboratory surveillance of Streptococcus pyogenes

A newly developed MLVA seven-loci scheme for Streptococcus pyogenes is described. The method can be successfully applied by using both agarose gel with visual inspections of bands and Lab on Chip technology. The potential of the present MLVA has been tested on a collection of 100 clinical GAS strains representing the most common emm types found in high-income countries plus 18 published gap-free genomes, in comparison to PFGE and MLST. The MLVA analysis defined 30 MLVA types with ten out of the considered 15 emm types exhibiting multiple and specific MLVA types. In only one occasion the same MLVA profile was shared between isolates belonging to two different emm types. A robust congruency between the methods was observed, with MLVA discriminating within clonal complexes as defined by PFGE or MLST. This new MLVA scheme can be adopted as a quick, low-cost and reliable typing method to track the short-term diffusion of GAS clones in inter-laboratory-based surveillance.

Resilient information networks for coordination of foodborne disease outbreaks

Foodborne disease outbreaks are increasingly being seen as a greater concern by public health authorities. It has also become a global research agenda to identify improved pathways to coordinating outbreak detection. Furthermore, a significant need exists for timely coordination of the detection of potential foodborne disease outbreaks to reduce the number of infected individuals and the overall impact on public health security. This study aimed to offer an effective approach for coordinating foodborne disease outbreaks. First, we identify current coordination processes, complexities, and challenges. We then explore social media surveillance strategies, usage, and the power of these strategies to influence decision-making. Finally, based on informal (social media) and formal (organizational) surveillance approaches, we propose a hybrid information network model for improving the coordination of outbreak detection.

Molecular typing of Chinese Streptococcus pyogenes isolates

Streptococcus pyogenes causes human infections ranging from mild pharyngitis and impetigo to serious diseases including necrotizing fasciitis and streptococcal toxic shock syndrome. The objective of this study was to compare molecular emm typing and pulsed field gel electrophoresis (PFGE) with multiple-locus variable-number tandem-repeat analysis (MLVA) for genotyping of Chinese S. pyogenes isolates. Molecular emm typing and PFGE were performed using standard protocols. Seven variable number tandem repeat (VNTR) loci reported in a previous study were used to genotype 169 S. pyogenes geographically-diverse isolates from China isolated from a variety of disease syndromes. Multiple-locus variable-number tandem-repeat analysis provided greater discrimination between isolates when compared to emm typing and PFGE. Removal of a single VNTR locus (Spy2) reduced the sensitivity by only 0.7%, which suggests that Spy2 was not informative for the isolates screened. The results presented support the use of MLVA as a powerful epidemiological tool for genotyping S. pyogenes clinical isolates.

Outbreak of pyrazinamide-monoresistant tuberculosis identified using genotype cluster and social media analysis

SETTING

Monoresistance to pyrazinamide (PZA) has infrequently been associated with Mycobacterium tuberculosis.

OBJECTIVE

To report an outbreak of PZA-monoresistant M. tuberculosis in Virginia involving two genotype clusters from December 2004 to August 2010.

RESULTS

Thirty cases were identified involving a predominantly young, US-born population with histories of substance use and incarceration and a large proportion of children aged <15 years (n= 6, 20%); of these, 23 cases (77%) were culture-confirmed as M. tuberculosis complex. DNA fingerprinting and molecular analysis of the PZA resistance gene, pncA, demonstrated a clonal strain that was not M. bovis. Genotypic data provided the initial link between seemingly unrelated cases, and helped reveal a historic genotype cluster of cases from 2004. Further genotype cluster and contact investigation procedures, including the novel use of the social networking website Facebook.com, revealed additional links between the 2004 and 2009 genotype clusters and described an ongoing, extensive outbreak necessitating an enhanced screening and treatment protocol for contacts.

CONCLUSIONS

This outbreak demonstrates how tuberculosis can spread through a young, vulnerable population. The use of genotypic data and the novel incorporation of social media investigations were critical to understanding the settings and context of infectivity.